1. Field of the Invention
The present invention relates to a toner used for a developer for developing a latent electrostatic image in electrophotography, electrostatic recording, electrostatic printing, or the like; a developer using the toner, and an image forming method using the toner.
2. Description of the Related Art
Generally, the term “carbon neutral” is used as a definition relating to biomass materials composed of organic materials. When such a biomass material is burned, carbon dioxide is released to the atmosphere, and the carbon contained in the carbon dioxide is derived from a carbon dioxide that has been absorbed by the biomass material through photosynthesis from the atmosphere in the process of growing. Therefore, it can be considered that even when such biomass materials are used, the amount of carbon dioxide in the air will not increase as a whole. Such a nature or property is referred to as “carbon neutral”.
Conventionally, components of toner, in particular, binder resins are substantially dependent on fossil resources, and thus it is said that carbon dioxide released from discarded toner and paper printouts is brought back into air, causing global warming, etc. The conversion from limited resources of fossils to biomass resources as reproducible resources can also be said to be a conversion into continuously reproducible resources, in terms that living organisms are produced from solar energy, water, and carbon dioxide. The conversion technology has been desired.
As components of a toner obtained from such reproducible resources, releasing agents such as carnauba wax, Candelilla wax, are exemplified. These releasing agents are mixed in toner to impart releasing properties to the toner during fixing. Since the amount of a releasing agent mixed therein is usually several percent by mass, only mixing of the releasing agent is far from satisfaction in view of carbon neutral.
Meanwhile, as to a technology focused on biodegradability from the viewpoint of environmental protection, use of biodegradable resins such as polylactic acids (PLAs) as binder resins in toner is studied. For instance, the following have been proposed: (1) a toner containing a polylactic acid (PLA) obtained by dewatering condensation (see Japanese Patent (JP-B) No. 3343635), (2) a toner containing a terminal-modified PLA (see Japanese Patent (JP-B) No. 2909873), (3) a toner containing a copolymer between terpene phenol and PLA as essential ingredients (see Japanese Patent (JP-B) Nos. 3785011 and 3779221), (4) a toner using PLA whose particle size and particle size distribution are defined (Japanese Patent Application Laid-Open (JP-A) No. 2004-126066), and (5) a toner containing a biodegradable resin and a vegetable wax in which the amount of wax ester is specified (see Japanese Patent (JP-B) No. 2597452).
However, in reality, a toner using biomass material required for sufficiently meeting requirements for carbon neutral and technologies related thereto have not yet been proposed so far.